Improved drying furnace and oven



J. K.-CALDWELL.

. l Brick Kiln., l No. 88,444. Patented March 30,1869'.

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UNITED STATES PATENT OEEIoE.

J. K. CALDWELL, OF ALLEGHENY CITY, PENNSYLVANIA.

IMPROVED DRYING FURNACE AND OVEN.

Specification forming part of Letters Patent No. 88,444, dated Jarch 30, 1869.

To all whom it may concern Be it known that I, J. K. CALDWELL, of Allegheny City, in the county of Alleghen y, and in the State of Pennsylvania, have invented certain new and useful Improvements in Drying Furnace and Oven and do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanyin g drawings, and to the letters of reference marked thereon.

My invention relates to an improvement on the drying apparatus patented by me January 21,1868;A and it consists, first, in the construction of the basement, in which the furnace and radiating-pipes are placed; second, in the application of two or more ,radiating-pipes passing from the furnace through the basement, so as to furnish a large amount of radiating-surface; third, in ledges or walls, either perpendicular or concave `at their upper part, on

which to place the track, and to conduct the heat toward the middle of the oven; fourth, in the application of one or more cold-air pipes, with small openings facing the radiating-surface of a furnace, so as to force, by means of a fan or blower, a current or jets of cold air on the radiating-surface of the furnace; fifth, in the application of a series of valves in the top or roof of a drying-oven to furnish an outlet for the saturated air, and so arranged as to have graduated openings to correspond with those parts of the oven where the amount of moisture or saturated air is greatest; sixth, in the use of perforated arched sheets over the radiating-pipes, with graded perforations, so asto admit the upward passage of a part of lthe heat from the furnace and radiating-pipes and conduct the other part of the heat into the oven.

In order to enable others skilled in the art to which my invention appertains to make and use the same, I will nowproceed to describe its construction and operation, referring to the annexed drawings, which form a part of this specification, and in which- Figure l is a longitudinal vertical section. Fig. 2 is a vertical cross-section taken through the line :r x, Fig. l; and Fig. 3 is a ground section taken through the line y y, Fig. 2.

A represents a drying-house of any approved size or shape, with doors B B at either end.

Under the frontend of the drying-house I place a furnace, X, with grate-bars a a., arched roof b, door c, and elsewhere closed on all sides except on the rear side, whence smoke-pipes C C lead back to the iiues D in the rear part of the drying-house.

To secure an increased amount of heatingsurface, I make Va chamber, cl, around -the arched roof b of the furnace; and along the sides of the dryin g-house I place ledges or walls E E, either perpendicular or concave, which walls are of the same height as the roof of the chamber d, forming between said walls a basement, F, through which the smoke-pipes G C pass from the furnace to the ue D. Said pipes may either be suspended or rest on supports in the basement.

Along' the upper inner edges of the walls E E are placed the rails e e, forming the track for the drying-cars, said rails extending across the roof to the chamber d over the furnace. Thus it will be seen that the walls or ledges E E serve a double purpose-as a support 0I' foundation for the track on which the dryingcars are moved, and also, which is the more important purpose, to contract the space where the heated air will escape. There being no space for the air to escape, except in the middle, between the rails e e, on which the dryingcars are placed, none of the heated air. is wasted, butall of it comes directly in contact with the articles on the cars to be dried, and thus saving fuel.

In the chamber d, I place one or more coldair pipes, f f, opening into the external atmosphere, and having a series of small openings, t' 1'-, facing the arched roof b of the furnace, so as to force, by means of a fan or blower, a current or jets of cold air on the radiating-surface of the furnace. This cold-air pipe may be placed in any desirable positions, so as to most eifectually bring the cold air in contact with the furnace.

The chamber d, being open at the rear, allows the air thus heated to pass into the basement F, and coming there in contact with the radiating-pipes G C, it is still more heated before it is discharged into the drying-house A.

The space between the rails e e is covered with a series of perforated arched sheets, G G. The perforations in these sheets are so arranged as to increase in size or number, or both, the farther from the furnace they are situated. Thus it will be seen that near the furnace only a small portion of the heat is admitted upward, and the balance passes farther onward, and by graduating the perforations, as above described, the heat in the dryinghouse will become uniform. The radiatingsurface of the pipes C C acting in a measure to make up for the loss of heat in the air while passing through the basement F, and the perforations in the arched sheets G G being graduated, the quantity of hot air discharged into the drying-house is increased in exact proportion to the loss in heat it has sustained during its passage through the basement.

lAs the hot air is discharged into the drying-house and comes in contact with the articles to be dried it becomes saturated with moisture, and it is well known more so farther from the furnace than nearerto it. The air thus moistened being unfit for drying purposes, it becomes necessary to allow it to escape from the drying-house; but in dryinghouses heretofore constructed no account has been taken of the increase in moisture contained in the air. By the usual modes of discharging the saturated air from the dryinghouse, either part of the air not yet moistened has been discharged or a part already moistened has been reta-ined, thus retarding the drying process. To remedy this evil I place in the' roof of the drying-house a series of valves, I I, with openings increasing in size from front to rear, which openings may be opened or closed by means of caps 71. h suspended from a shaft, m, and turned by a lever, a, all so arranged that the caps h h are raised or lowered at the same time, but with a velocity increasing in exact proportion as they are situated farther from the front of the drying-house.

ln the drawings I have represented these valves as being square flues, with V-shaped openings O O at the top; but they may be of any shape desired, and operated by any suitable means, so that their openings are graduated in the manner above described. By this arrangement it will readily be seen that more air is discharged from the rear part of the drying-house, where the air sooner becomes saturated, than at the front part, where it does not, soon become moist.

' Having thus fully described my invention, what I claim-as new, and desire to secure by Letters Patent, is-

l. rIhe furnaceiX, with its arched roof b, track-supporting ledges E, perforated arched sheets Gr, placed over said furnace and above the radiating-pi pes C, leading from the rear of the furnace, through the hot-air chamber F, to the cross-i'lues D, all arranged together substantially as and for the purposes herein set forth.

2. The arrangement of the perpendicular or concave car-supporting ledges or walls E E in the drying-house A for conducting the heat to the central portions of the chamber, constructed substantially as specified.

3. The arrangement, in combination with the furnace X, of the cold-air pipes j', with perforations c' c', that face the exterior convex surface of the radiating-arch b, whereby jets of cold air may be transmitted by any exterior apparatus, substantially as speciiied.

4. The series of valves I I, with graduated openings connected and simultaneously operated by one and the saine rod, substantially as herein described.

5. The arrangement of the movable arched plates G G, provided with graduated perforations, and placed over' the chamber F, between the ledges E E, substantially as shown and described.

In testimony that I claim the foregoing I have hereunto set my hand this 16th day of December, 1868.

J. K. CALDWELL.

Witnesses:

J. M. MASON, LEOPOLD EVERT. 

